AFB Compression: Explained and Optimized

Hey everyone,

During the breakdown repair of my vehicle (which included replacing the fuel injection pump and fuel pump, with an engine having approximately 160,000 km mileage and a vehicle mileage of 290,000 km, manufactured in 1999, with a new engine installed around May 2002), a compression test was also performed.

I don't have the documents readily available right now, but I remember that the compression was approximately 25 (I don't recall the unit) for all cylinders, with a variation of about plus or minus 3. However, the compression for cylinder #1 was only about 17.

The engine is actually running normally (very loud, but it has been like that for 7 years), and it's pulling well.

Since I had a lot of trouble with the first engine due to worn camshafts, I wanted to finally address that issue.

What can I read from such compression measurements? In my old days of tinkering with Ford engines, it usually ended up being either a head gasket issue or needing to tighten the spark plugs... } but those were also somewhat simpler engines.

Regards,
Felix.

I assume that the engine was cold during this measurement.
Therefore, it is not necessarily very informative.
Do it when it's warm. It's unlikely anyone will have it at pressures below 20 bar.

AFN:

new: 25...31 bar overpressure.
Wear limit: 19 bar overpressure.

Allowable pressure difference between all cylinders: 5 bar.